The use of cross-linked polymeric material in ink jet receiving films is a well-known technology. Common cross-linking mechanisms involve exploiting functional group chemistry within the polymer backbone. This type of cross-linking is commonly used to give water insolubility to the coated product.
U.S. Pat. No. 5,219,928 discloses a liquid-absorbent composition comprising (a) a polymeric matrix component comprising cross-linked silanol moieties, said silanol moieties being in pendant groups of said matrix component, and (b) an uncross-linked liquid-absorbent component comprising at least one water-absorbent polymer.
U.S. Pat. No. 5,439,739 discloses an ink jet recording medium comprising a support and at least one ink jet receiving layer, said ink receiving layer comprising a water-soluble polymer obtained by copolymerizing 10-50 parts by weight of a quaternary salt monomer, 1-30 parts by weight of an amino group containing monomer or a carboxyl group containing monomer and 20-80 parts by weight of a monomer selected from acrylamide, methacrylamide, N,N-dimethacrylamide, N-isopropylacrylamide, diacetone acrylamide, N-methylolacrylamide, 2-hydroxyethyl(meth)acrylate, and N-vinylpyrrolidone, and 0.1-30 parts by weight of a cross-linking agent.
U.S. Pat. No. 5,192,617 discloses a transparent film comprising a transparent backing bearing on at least one major surface thereof a layer formed from a composition comprising (a) a polymeric matrix component comprising cross-linked tertiary amino moieties and carboxyl moieties, said matrix component having one carboxyl moiety for each amino moiety that has been cross-linked, and (b) a liquid absorbent component comprising a water-absorbent polymer that is not cross-linked.
U.S. Pat. No. 4,528,242 discloses an ink jet recording transparency having a coating which is clear and comprises a mixture of a carboxylated polymer or copolymer, having a molecular weight of about 50,000 to 1 million, and a polyalkylene glycol having an average molecular weight of about 5,00 to 25,000, preferably 15,000 to 25,000, the glycol being present in an amount of about 5% to 70%, preferably 10% to 25%, by weight of said polymer.
Traditional cross-linking through functional groups within the backbone of the polymer results in a dense, tightly packed product. Although it is not difficult to make such a material water insoluble, it is difficult to obtain liquid receptivity with such a technique. In particular, the ability of such a material to absorb liquid ink is often compromised. Ink jet coatings produced with such materials are often unable to accept very high ink loadings and images are often of poor quality.